1. Field of the Invention
This invention relates generally to tamper indicating closures.
2. Description of the Prior Art
Tamper indicating closures including an integrally formed cap, a tamper indicating ring, and spaced thin webs, or bridges, for joining the cap to the ring are well known; see, for example, U.S. Pat. No. 3,463,341, granted Aug. 26, 1969 to M. R. Fields.
However, the Fields closure is applicable only to containers having radially projecting tongues molded or otherwise secured thereon; such tongues extend into the gaps between the adjacent webs. When one attempts to remove the closure from the container, the tongues shear the webs and separate the tamper-indicating ring from the cap. Continued rotation of the cap exposes the contents of the container, and the cap, minus the tamper-indication ring, may be re-used as an ordinary cap.
Some shortcomings of the Fields tamper-indicating closure are readily apparent. The webs must be molded within precise dimensional tolerances, for they must be sufficiently flexible in the axial direction for the closure to be assembled upon the container over the projecting tongues by high speed, automated machinery, and yet be strong enough in the radial direction to retain the cap on the tamper-indicating ring in fixed position. Also, the container would have to be formed of a readily moldable material, such as plastic, glass, or the like that would permit the formation of the radially projecting, resilient tongues.
Other plastic molded tamper-indicating closures have been developed, but such closures suffer from one or more of the shortcomings noted in the preceding paragraph.